TB-500
Aliases: Thymosin Beta-4 fragment · TB4-frag
Last verified: 2026-09-23
The short version
TB-500 is a fragment of Thymosin Beta-4, a peptide involved in progenitor cell mobilization and tissue repair. Animal data show accelerated wound healing and muscle recovery, but no controlled human data exist — the exception being full Thymosin Beta-4, which reached phase II trials for wounds and dry eye. Everything known in humans comes from community self-reports. The gray supply is unregulated, and it is often paired with BPC-157 in the 'Wolverine stack'.
Identity & type
- Molecular type
- fragment
- Sequence / structure
- LKKTETQ (region 17–23 Thymosin beta-4)
- Molecular weight
- ~847 Da
- Origin
- Synthetic fragment (region 17–23, LKKTETQ) of the natural peptide Thymosin Beta-4.
Mechanism of action
Regulates actin dynamics (binds G-actin), promotes cell migration, angiogenesis and reduces inflammation in injured tissue.
not confirmed in humans
Dosing & routes
Official / clinical context
No approved official document exists for TB-500. Any protocols mentioned are to be read as information, not as a recommendation.
Regulator-approved labeling and published study designs — never a recommendation.
Community-reported practice
Common: 2–2.5 mg SC twice weekly for 4–6 weeks ("loading"), then weekly maintenance. Users report improved tissue flexibility, faster recovery from strains and reduced stiffness after 2–4 weeks. Often combined with BPC-157; some users feel nothing without the higher dose.
Unverified self-reports. Not medical advice. Not endorsement.
Expected effects (community)
Users report improved tissue flexibility, faster recovery from strains and reduced stiffness after 2–4 weeks. Often combined with BPC-157; some users feel nothing without the higher dose.
Protocol — official vs community
Official / label
No official protocol. TB-500 (TB-4 fragment) has no approved product; the parent molecule thymosin beta-4 has trial data only in dermal/wound contexts.
Duration: —
WADA-prohibited (S0). No registered human trial of TB-500 as an injectable recovery agent exists.
Community (anecdotal)
2–2.5 mg SC twice weekly (loading), then 2 mg every 1–2 weeks maintenance; or flat 2 mg 2× weekly.
- Cycle:
- 4–8 weeks, paired with BPC-157 in the Wolverine pattern.
- Break:
- 2–4 weeks off.
The loading/maintenance split is community convention, not pharmacology — the half-life rationale behind it is asserted, not demonstrated.
Human evidence
No controlled human trials of the TB-500 fragment. Parent Tβ4 had phase II studies (wound healing, dry eye) that did not lead to approval.
Preclinical evidence
Data from rodent models of muscle injury, wounds and cardiac injury; mechanism linked to actin cytoskeleton regulation and cell migration via the LKKTETQ motif.
Known risks
- Unknown human safety and immunogenicity of the fragmentcharacterized
- Unregulated supply; contamination riskcharacterized
- Theoretical risk of altered tumor healingtheoretical
Teal: characterized in clinical/labeling contexts. Amber: theoretical or reported outside controlled settings.
Unknowns & evidence gaps
- Human pharmacokinetics and active dose
- Whether Tβ4 effects transfer to the short fragment at all
Frequently asked questions
References
- Goldstein A.L. et al., Thymosin beta-4 i zarastanje rana (review literatura)
- Early clinical program of Tβ4 (RGN-259 eye drops, phase II reports)